1. Technical Field
Example embodiments relate to a wireless communication technology. For example, at least some example embodiments relate to a contactless communication chip, a contactless communication device including the contactless communication chip and/or an electronic system including the contactless communication device.
2. Description of the Related Art
Recently, a contactless communication device such as a near field communication (NFC) device has been extensively employed in mobile devices.
A contactless communication device can operate in a reader mode (i.e., operates as a contactless communication reader for contactlessly reading a contactless communication card) or in a card mode (i.e., operates as a contactless communication card). In the reader mode, the contactless communication device emits an electromagnetic wave to communicate with an external contactless communication card. In the card mode, the contactless communication device communicates with an external contactless communication reader based on an electromagnetic wave emitted by the external contactless communication reader.
Generally, the contactless communication device may emit an electromagnetic wave in the reader mode using a clock signal received from outside or using a clock signal generated internally, such that the electromagnetic wave emitted by the contactless communication device has a desired frequency defined in, for example, a communication standard.
If the contactless communication device emits an electromagnetic wave using a dock signal received from outside, a manufacturing cost and a size of the contactless communication device may increase.
On the other hand, if a contactless communication device emits an electromagnetic wave using a clock signal generated internally, while the manufacturing cost and size may decrease, a correctness of a frequency of the electromagnetic wave may decrease and the frequency of the electromagnetic wave may be changed according to temperature.